\begin{equation}
  \ell
  _{j}(x):= \prod
  _{0 \leq m \leq k; \quad m \neq j}\frac{x - x_m}{x_j - x_m}= \frac
  {x - x_0}{x_j - x_0}\cdots \frac
  {x -
    x_{j - 1}}{x_j -
    x_{j - 1}}\frac
  {x -
    x_{j + 1}}{x_j -
    x_{j + 1}}\cdots \frac
  {x - x_k}{x_j - x_k}
\end{equation}

\begin{equation}
  W =
  \begin{bmatrix}
    1 & 0 & 0 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 & 0 & 0 \\ 0 & 0 & 1 & 0 & 0 & 0 \\ 0 & z_i   & 0 & 1 & 0 & 0         \\ -z_i    & 0 & 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 0 & 0 & 1
  \end{bmatrix}
\end{equation}

\begin{itemize*}
  \item dünne Platten, kleine Verformungen \item dünne Platten, große Verformungen \item dicke Platten
\end{itemize*}
